Kandinsky analyses in his writings the geometrical elements which compose every painting, namely the point and the line, as well as the physical support and the material surface on which the artist draws or paints and which he calls the basic plane or BP. He doesn’t analyze them on an objective and exterior point of view, but on the point of view of their inner effect on the living subjectivity of the observer who looks at them and lets them act on his sensibility.

The point is, in practice, a small stain of color put by the artist on the canvas. So the point used by the painter is not a geometric point, it is not a mathematical abstraction, it possesses a certain extension, a form and a color. This form can be a square, a triangle, a circle, like a star or even more complex. The point is the most concise form, but according to its placement on the basic plane it will take a different tonality. It can be alone and isolated or put in resonance with other points or lines.

The line is the product of a force. It is a point on which a living force has been applied in a given direction, the force applied on the pencil or on the paint brush by the hand of the artist. The produced linear forms can be of several types: a straight line, which results from a unique force applied in a single direction, an angular line, which results from the alternation of two forces with different directions, or a curved or wave-like line produced by the effect of two forces acting simultaneously. A plane can be obtained by condensation, from a line rotated around one of its ends.

Taken from http://en.wikipedia.org/wiki/Wassily_Kandinsky